Susan Boyle burst into tears of joy when hundreds of fans threw her a surprise birthday party in Tokyo.

The Britain's Got Talent star turns 49 on April 1 and is in Japan to perform on her birthday, but was delighted with early festivities when fans brought out a cake with candles and burst into a rendition of Happy Birthday, the Daily Mirror reports.

Susan apparently gasped in shock when she opened a present to find a £6,000 diamond and gold bracelet from music mogul Simon Cowell.

A source said: "She couldn't believe her eyes and burst into tears.

"She had seen the bracelet in a magazine and said, 'Gosh, imagine owning something like that.' So Simon tracked it down at Harrods."

Susan will sing with the Yomiuri Nippon Orchestra before 10,000 people at the famous Budokan arena.